SparkFun Forums

[chriscross93]

My Ethernet shield (seemingly) fried itself out of the blue last night. When power is applied the voltage regulator gets too hot to touch almost instantly. Has anybody ever heard of this before? Given the fact that the shield costs more than an Arduino itself, I would like to attempt a repair if possible.

Thanks for any input.

[waltr]

My guess is that some component shorted. First suspects are any Tantalum caps then electrolytics. Unfortunately these need to be un-soldered to test with an Ohm meter.

ICs could also short. The finger (don't burn it) test can find these parts.

Good luck

[chriscross93]

That is what I'm figuring as well, it appears to be the voltage regulator. My next problem seems to be finding a new regulator to swap out. The markings of the one on the board yield no relevant Google results.

Markings:

(ON) RNS - Presumably ON semiconductor
2693

[waltr]

If a component on the output of the regulator is shorted then the regulator WILL get hot but the regulator isn't bad. You can try disconnecting the regulator output and test to see if it is putting out the correct voltage without a load. Then check the regulator's output circuit with an Ohm meter to see if there is a short elsewhere on the board.

[chriscross93]

Good point. Off to test....

[chriscross93]

Being that I have absolutely no surface mount soldering experience, I am hesitant to start removing components. That said, looking back I am pretty sure what fried the shield in the first place. When connecting power the last time, I likely plugged the 5v rail into the 3v terminal. Can anybody pinpoint a component that likely would of fried as a result? Thanks for the input.